Sending JSON to Schematic Ipsum - ios

Question

I'trying to get some random JSON from http://schematic-ipsum.herokuapp.com/ but I'm getting a response code 400.
Here is the code I'm using
+ (NSArray *)postData:(NSDictionary *)arguments toServer:(NSString *)urlString
{
NSArray *dataToReturn;
// if urlString is nil, we default it to our server
if(!urlString) urlString = JSON_SERVER;
// of course we need to turn the string into a valid array
NSURL *url = [NSURL URLWithString:urlString];
/*
prepare the post
*/
// we need to catch possible errors
NSError *error;
// turn our arguments into NSData
NSData *postData = [NSJSONSerialization dataWithJSONObject:arguments options:0 error:&error];
// we need the post' length
NSString *postLength = [NSString stringWithFormat:#"%lu", (unsigned long)[postData length]];
// create the url request
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
[request setURL:url];
[request setHTTPMethod:#"POST"];
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
[request setValue:#"application/x-www-form-urlencoded;charset=UTF-8" forHTTPHeaderField:#"Content-Type"];
[request setHTTPBody:postData];
// here we'll check the server response
NSHTTPURLResponse *response = nil;
// here's our data from the server
NSData *urlData=[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
if ([response statusCode] >=200 && [response statusCode] <300)
{
// all good, let's see what we've got
NSString *responseData = [[NSString alloc]initWithData:urlData encoding:NSUTF8StringEncoding];
NSLog(#"Response ==> %#", responseData);
// parse the response into a friendly format
dataToReturn = [[NSArray alloc] initWithArray:[self returnJSONFromData:urlData]];
} else {
// somethin went wrong
NSLog(#"Response code: %ld", (long)[response statusCode]);
// check if it's our fault
if (error) {
NSLog(#"Server error: %#", [error localizedDescription]);
}
}
// return our formatted array or nil
return dataToReturn;
}
+ (NSArray *)returnJSONFromData:(NSData *)urlData
{
NSArray *dataToReturn;
NSError *e = nil;
NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData: urlData options: NSJSONReadingMutableContainers error: &e];
if (!jsonArray) {
NSLog(#"Error parsing JSON: %#", [e localizedDescription]);
dataToReturn = #[e];
} else {
dataToReturn = [[NSArray alloc] initWithArray:jsonArray];
NSLog(#"data from json: %#", dataToReturn);
}
return dataToReturn;
}
and I'm calling it like this, using a demo JSON from their website:
NSDictionary *post = #{ #"type": #"object", #"properties": #{ #"id": #{ #"type": #"string", #"ipsum": #"id" }, #"name": #{ #"type": #"string", #"ipsum": #"name" }, #"email": #{ #"type": #"string", #"format": #"email" } }};
[RetrieveDataFromServer postData:post toServer:#"http://schematic-ipsum.herokuapp.com/"];

Answer 1

You need to respect the syntax of "Form Data" that the server takes. To obtain this, you can use Google Chrome "Inspect Element", choose "Network" tab then do a request and you'll see this:
Look at "Form Data" section and you'll find out your problem, it's because you didn't pass the right structure to server so that the server doesn't understand.
I took the defaults parameters of server which is:
{
"type": "object",
"properties": {
"id": {
"type": "string",
"ipsum": "id"
},
"name": {
"type": "string",
"ipsum": "name"
},
"email": {
"type": "string",
"format": "email"
},
"bio": {
"type": "string",
"ipsum": "sentence"
},
"age": {
"type": "integer"
},
"avatar": {
"type": "string",
"ipsum": "small image"
}
}
}
So the data must be structured like this:
type:object
properties[id][type]:string
properties[id][ipsum]:id
properties[name][type]:string
properties[name][ipsum]:name
properties[email][type]:string
properties[email][format]:email
properties[bio][type]:string
properties[bio][ipsum]:sentence
properties[age][type]:integer
properties[avatar][type]:string
properties[avatar][ipsum]:small image
And don't forget to encode with percentage before sending it to server or you will fail again.
I tried to implement a method that take your dictionary and return the formatted form data, it works fine for this case but I'm not sure in a more general context. I'll post it here for you as a reference, it's really a mess, sorry for that but I don't have enough time for commenting.
- (NSString *)formatFormData:(NSDictionary *)dictionary
{
NSMutableArray *arrayPrefix = [NSMutableArray array];
NSMutableArray *arrayResult = [NSMutableArray array];
[self structureString:dictionary arrayPrefix:arrayPrefix arrayResult:arrayResult];
return [arrayResult componentsJoinedByString:#"&"];;
}
- (void)structureString:(NSDictionary *)dictionay arrayPrefix:(NSMutableArray *)arrayPrefix arrayResult:(NSMutableArray *)arrayResult
{
for(NSString *key in dictionay.allKeys)
{
NSObject *obj = [dictionay objectForKey:key];
if([obj isKindOfClass:[NSDictionary class]])
{
[arrayPrefix addObject:key];
[self structureString:(NSDictionary *)obj arrayPrefix:arrayPrefix arrayResult:arrayResult];
}
else
{
NSMutableString *string = [[NSMutableString alloc] initWithString:#""];
for(int i = 0; i < arrayPrefix.count; i++)
{
NSString *eachPrefix = arrayPrefix[i];
if(i == 0)
{
[string appendString:eachPrefix];
}
else
{
[string appendString:[NSString stringWithFormat:#"[%#]", eachPrefix]];
}
}
if(arrayResult.count == 0)
{
[string appendString:[NSString stringWithFormat:#"%#=%#", key, obj]];
}
else
{
[string appendString:[NSString stringWithFormat:#"[%#]=%#", key, obj]];
}
[arrayResult addObject:string];
}
}
}
And in your current method, add these lines:
- (NSArray *)postData:(NSDictionary *)arguments toServer:(NSString *)urlString
{
// omitted
// turn our arguments into NSData
NSData *postData = [NSJSONSerialization dataWithJSONObject:arguments options:0 error:&error];
NSString *stringTemp = [[NSString alloc] initWithData:postData encoding:NSUTF8StringEncoding];
stringTemp = [self formatFormData:arguments];
// encode form date before sending to server
stringTemp = [stringTemp stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
postData = [stringTemp dataUsingEncoding:NSUTF8StringEncoding];
// omitted
}